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Effects of Pretreatment of Alkali-degreasing Solution for Cu Seed Layer (약알칼리탈지 용액에서의 구리 Seed 층의 전처리 효과)

  • Lee, Youn-Seoung;Kim, Sung-Soo;Rha, Sa-Kyun
    • Journal of the Korean Vacuum Society
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    • v.21 no.1
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    • pp.6-11
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    • 2012
  • In order to understand a process of contaminants removal on surface of Cu seed layer (Cu seed/Ti/Si) by sputter deposition, we investigated the changed morphology and states of Cu seed surface after pretreatment in alkali degreasing Metex TS-40A solution according to dipping time. After TS-40A pretreatment, the surface morphology with clearer grains was observed by Field emission scanning electron microscope and the changed surface chemical states and impurities on surface of samples were checked by X-ray photoelectron spectroscopy. Dipping time in TS-40A solution had very little effect on surface of Cu seed layer. After pretreatment, much carbons and little oxygens on surface of Cu seed were eliminated and the decrease of peaks corresponded to O=C and $Cu(OH)_2$ was estimated. However, Si content (=silicate) was detected on sample surface. We think that the silicate impurity forms on Cu seed by chemical reaction of TS-40A solution included silicate component. By pretreatment of alkali degreasing Metex TS-40A solution, it showed an excellent effect in removal of O=C and $Cu(OH)_2$ on Cu seed layer, but the silicate was formed on surface of Cu seed. Therefore, another cleaning process such as acid cleaning is required for removal of this silicate in use of this alkali degreasing.

The Study on Optimum Operation Conditions of Ceramic MF Membrane Process in Y Water Treatment Plant (Y 정수장 세라믹막 여과공정 최적 운영인자 평가)

  • You, Sang-Jun;Ahn, Hyo-Won;Park, Sung-Han;Lim, Jae-Lim;Hong, Sung-Chul;Yi, Pyong-In
    • Membrane Journal
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    • v.24 no.3
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    • pp.201-212
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    • 2014
  • This study was performed to discover the optimum operation conditions for the advanced water treatment using the ceramic membrane, introduced the first in the nation at the Y water treatment plant (WTP). The result of investigation to find the optimum operation conditions which can continue preserving the filtration performance as well as satisfying both the economics and the water quality is as follows. In the ordinary water quality condition of the Y WTP, the optimum filtration time(the backwash period), which can minimize the production of backwash waste and preserve the membrane performance was examined to be 4.0 hours on basis of institution capacity ($16,000m^3/day$). Examining the recovery rate of TMP from the chemical cleaning (CIP) discovered that the inorganic contaminants, which cause membrane fouling, such as iron, manganese, aluminum, were removed through the acidic cleaning using citric acid, whereas the membrane recovery rate was found to be low. But, on the other hand, the TMP was recovered to the initial value from the alkali cleaning using the NaOCl. Therefore, the main contaminant causing the fouling was determined to be hydrophilic organic compound( biopolymer). The membrane recovery rate is highly influenced by the temperature of the cleaning chemical. That is, the rate increased with increasing temperature.

Effects of Electricity Supporting Agents on the Characteristics of Electroplated Zinc Layer from Sulfuric Bath (황산욕에서 전기아연 도금 피막 특성에 미치는 전기전도 보조제의 영향)

  • 남궁성;이용진;정연수;전유택
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2000.05a
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    • pp.51-52
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    • 2000
  • 전기아연도금강판은 표면이 미려하고 희생방식력이 뛰어나기 때문에 주로 자동차와 가전, 건자재 등에 많이 사용된다. 현재 냉연 표면처리 제품들은 연속도금공정에 의해 생산되고 있으며 고전류밀도에 의한 고속생산과 도늠액 제조와 조성이 비교적 단순해야 하는 여러 가지 이유로 염산욕과 황산욕을 가장 많이 사용하고 있다. 최근에 신설된 당사의 전기도금공정은 수직형으로 황산욕에서 불용성 양극을 채용하여 아연을 전기도금하고 있다. 일반적으로 황산욕은 염산욕 대비 전기 전도성이 나빠 과전압이 크게 걸리므로 불용성 양극을 사용하여 극간 거리를 최소화할 필요가 있다. 그러나 $Ir0_2$가 코팅된 불용성 양극은 가격이 비싸기 때문에 극간 거리를 너무 짧게 하면 깡대에 의해 손상을 받을 수가 있어 극간 거리를 줄이는데 한제가 있다. 따리서 용액의 전도도들 증가시켜 과전합을 줄이기 위해서는 타사에서 현재 사용하고 있는 황산나트륨, 황산칼륨, 황산암모늄 등에 대한 검토가 필요하다. 전기전도 보조제들은 용액의 전기전도도 뿐만 아니라 도금층의 외관 및 미세구조에도 많은 영향을 주는 것으로 알려져 있다. 따라서 본 연구에서는 황산나트륨, 황산암모늄의 농도를 변화시켜 표면외관, 한계전류밀도, 미세구조, 우선배향성 등을 조사하여 최적의 물성을 갖는 아연 도금층을 얻기 위한 조건을 도출하고자 하였다. 전기아연도금용 소재로는 두께 0.8mm이고 크기가 $100{\times}120mm$인 중저탄소강 (0.02% C)을 사용하였으며 전처리 과정으로 탈지와 산세를 행하고 현장 도금액을 사용하여 다음과 같은 조건 하에서 아연도금을 행하였고 극간전합을 측정하였다. 도금 후 표면의 미세구조는 SEM을 사용하여 관찰하였으며 표면외관 특성을 분석하기 위해 광택도계(Tri- Microgloss-60-85)를 이용하여 입사각 $60^{\circ}$ 에서 광택도를 측정하였고, 색차계(Color Quest II Hunter Lab.)를 사용하여 백색도를 각각 측정하였다. 또한 X선 회절기를 이용하여 도금층의 우선 배향성을 분석하였다.

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Aldol Condensation over Acid-Base Bifunctional Metal-Organic Framework Catalysts (산, 염기 이원기능 금속-유기 구조체 촉매를 이용한 알돌 축합반응)

  • Chung, Young-Min
    • Clean Technology
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    • v.20 no.2
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    • pp.116-122
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    • 2014
  • Various types of MOFs (metal-organic frameworks) were prepared via hydrothermal and post-grafting methods and applied as catalysts for the synthesis of jasminaldehyde, one of the representative perfume intermediates, by Aldol condensation of benzaldehyde with heptanal. Although both acid and base sites could catalyze the reaction, the catalytic performance was strongly dependent on the physical properties as well as the nature of functionalization on MOFs. While the use of sulfonated MOF catalysts led to decrease of jasminaldehyde selectivity regardless of MOFs used, the selectivity change was found to rely on the MOF types in the case of the amine-functionalization. Among the catalysts tested, MIL-101 shows the best catalytic performance, which may suggest that MIL-101 has suitable acid properties to promote the Aldol condensation and the large pore of MIL-101 is also advantageous to alleviate the diffusion problem of bulky products.

Effects of Blasting and Acidic Treatment on the Corrosion Characteristics of Dental Implant Fabricated with Cp-Ti and Ti-6Al-4V Alloy (Cp-Ti와 Ti-6Al-4V 합금으로 제조된 치과용 임플란트의 부식특성에 관한 블라스팅과 산세처리의 영향)

  • Moon, Young-Pil;Choe, Han-Cheol;Park, Su-Jung;Kim, Won-Gi;Ko, Yeong-Mu
    • Journal of the Korean institute of surface engineering
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    • v.39 no.4
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    • pp.190-197
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    • 2006
  • The effects of blasting and acidic treatment on the corrosion characteristics of dental implant fabricated with Cp-Ti and Ti-6Al-4V alloy have been researched by using electrochemical methods. The fabricated implants were cleaned and sandblasted by $Al_2O_3$ powder and then acidic treatment was carried out in nitric acid solution. The surface morphology were observed using scanning electron microscope. The corrosion behaviors were investigated using potentiosat and EIS in 0.9% NaCl solution at $36.5{\pm}1^{\circ}C$. The potentio-dynamic test in 0.9% NaCl indicated that the corrosion potential of blasting and acidic treated implant was lower than that of non treated implant, but current density was higher than that of non treated implant. From the cyclic potentiodynamic test results of Ti implant, the passivation current density of blasting and acidic treated implant slightly higher than that of non treated implant. From A.C. impedance test results in 0.9% NaCl solution, polarization resistance($R_p$) value of blasting and acidic treated implant was lower than that of non treated implant. In case of blasting and acidic treated implant surface, the pits were observed in valley and crest of implant surface.

A Study of Contents Analysis on Questioning Daehan- Sin- Gygi - Focusing on the Contents of Physical Geography - (문답 대한 신지지 내용분석- 자연지리를 중심으로)

  • KANG, Chul-Sung
    • Journal of The Geomorphological Association of Korea
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    • v.17 no.4
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    • pp.17-27
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    • 2010
  • This article focuses on the period from the beginning of Twentieth, the period commonly regarded as the Enlightenment Period in Korea. Questioning Daehan-Sin-Gygi( 問答大韓新地誌) textbook consists of contents of physical geography aimed at rational and objective perception of the nature, within the frame of Sirak(實學) and Progressive Thoughts. In terms of contents organization, there are too wide range of facts and knowledge covered, with mechanical imitation of statement style of systematic and regional approach. Particularly, Geography textbook in this period attached greater importance to contents of physical geography than any other times. It is possible to conclude that real outcomes of geography education at the time contributed significantly to enlightenment of people and integration of the society. I consider that statement style of question-response used at the time is very worth-while.

A Study on Heavy Metal Concentrations in Waste Water Produced in the Casting Pickling Process at Dental Technical Laboratories (치과기공소 주조체 산세척과정에서 발생하는 폐수내 중금속 농도)

  • Jeong, Da-i;Sakong, Joon
    • Journal of Environmental Health Sciences
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    • v.44 no.1
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    • pp.55-62
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    • 2018
  • Objectives: This study set out to measure the heavy metal concentrations in waste water produced in the casting pickling process at dental technical laboratories and examine the actual state of its treatment. Methods:The investigator measured the concentrations of each heavy metal at 55 dental technical laboratories using an inductively coupled plasma optical emission system. Results: The annual usage of electrolytes was under 10 L in 50 (90.9%), and was 10L or more in five (9.1%) laboratories. Among the laboratories, 15 (27.3%) commissioned the treatment of waste,12 (21.8%) treated the waste with general sewage,and 28 (50.9%) treated the waste in aseptic tank. The arithmetic $mean{\pm}standard$ deviation and the geometric mean of chrome(Cr) were $75.3{\pm}50.9$ and 58.3 mg/L; those of cobalt (Co) were $112.3{\pm}106.7$ and 66.1 mg/L; those of nickel (Ni) were $62.9{\pm}83.5$ and 8.9 mg/L; those of molybdenum (Mo) were $17.1{\pm}13.4$ and 12.0 mg/L; those of iron (Fe) were $31.5{\pm}44.1$ and 6.2 mg/L; those of lead (Pb) were $0.3{\pm}0.3$ and 0.3 mg/L; those of beryllium (Be) were $3.6{\pm}3.6$ and 2.0 mg/L. The hydrogen ion concentration was under pH 2 across all the samples. Conclusions: The findings show that the dental technical laboratories were not doing well with the separation, storage, collection, and treatment of the electrolytes they discarded, and that most of the electrolytes were introduced through the general sewage or aseptic tank. The causes of this include alack of perception among the practitioners at dental technical laboratories and contracted companies avoiding collection for economic reasons. There is a need for education to improve the perceptions of waste water treatment among the practitioners at dental technical laboratories. Environment-related departments should be stricter with legal applications in the central and local governments. It is also required to provide proper management of commissioned treatment.

Research of private landscape architecture of the Tang Era in ancient China -based on excavated excellent articles and a book <洛陽名園記> called Nakyangmyungwonki- (중국 고대 당대(唐代) 민간 조경[사가원림(私家圓林)] 연구 - 출토된 명기(明器)와 낙양명원기를 중심으로 -)

  • Park, Kyung-Ja
    • Korean Journal of Heritage: History & Science
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    • v.38
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    • pp.285-303
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    • 2005
  • Through the excavated excellent articles of the Tang era, we have considered the building techniques and styles of a square pavilion, an octagonal pavilion, a miniature hill, a pond, etc., could read building techniques of the scenic structures on ancient literatures including records and additionally about their poetical life at that time and inquired into the arrangement, structure, building techniques, etc. of a miniature hill, a pond, a pavilion, a flowerplant, etc., on Nakyangmyungwonki. Thus, under the research on the private landscape architecture, especially the nobility gardening, around excavated excellent articles and literatures, 'A miniature hill(假山) and a pond for landscaping views formed the center of a garden, and additionally a pavilion was built and flowerplants were set. The miniature hill of laying stones and having a carven, steeping, stratifying, looking like dyed green and birds' singing among hills and eating water on the lakeshore${\ldots}$' was expressed. The pond of digging in the ground and conducting water had its water system developed. There were several kinds of pavilions such as 廳, 堂, 館, 亭, 臺, 樓, 閣, 榭, etc. As examples of landscaping plants, there were a bamboo, a lotus flower, a peony, aromatic trees a pine, a korean spindle tree, a big cone pine, an empress tree, a wild walnut, a peach, a plum, a Japanese apricot tree, an apricot tree, a chrysanthemum, arrowroot vines, etc. Thus, the garden of the Tang era, abundant, diverse and excellent, enjoyed the prime of the period of prosperity. Due to cultural exchange, it is supposed that the period of united Shilla of the same age would meet with the period of prosperity in the developmental history of Korea landscape, based on the nobility garden system '4 different dwelling-houses every season on a record "四節游宅"'.

The Cultural Landscapes of Wuyi-Gugok of China as seen from the 「Landscape of the Jiuqu River in the Wuyi Mountain」 in British Library (대영도서관 소장 「무이산구곡계전도(武夷山九曲溪全圖)」로 본 중국 무이구곡의 문화경관상)

  • Cheng, Zhao-Xia;Rho, Jae-Hyun;Jiang, Cheng
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.37 no.4
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    • pp.11-31
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    • 2019
  • Taking the painting, 「Landscape of the Jiuqu River in the Wuyi Mountain」 as the study object, which was produced in the middle of Qing Dinasty and collected by the British Library, this paper analyzes the scenery names recorded in the painting, and describes the landscape of the mountain, port and ships, architectural elements, civil elements, character, stone inscription and other scenery in the painting. The investigation results of the cultural landscape properties of each Gok are as follows: According to statistics, there are 28 architectural elements in the painting, including 7 pavilions (25%), 4 temples (14.3%), 3 Colleges and Taoist temple (10.7%), 2 Dowon(道院) and villages (7.1%); 29 civil elements, including 9 holes (31%), 6 Historical Sites (20.7%), 3 Stations(臺) (10.3%), 2 Ferries, 2 Bridges, and 2 Ponds (6.9%), 1 Garden, 1 Gate, 1 Mine(坑), 1 Well and 1 Remains(3.4%). These physical factors and civil factors are the important relics reflected the cultural landscape attributes of Wuyi-Gugok in the middle of the 18th century. Among the shape element in each Gok, the 1st Gok have 12 shape elements(21.1%), the 5th Gok 11(19.3%), the 4th Gok 9(15.8%), the 9th Gok 8(14%), the 3rd Gok 7(12.3%), the 6th Gok 4(7%), the 2nd Gok 3(5.3%), the 7th Gok 2(3.5%), and the 8th Gok 1(2%). Through collation, it is found that the 1st Gok, 5th Gok and 4th Gok have more prominent cultural landscape characteristics. In addition, according to the description of scenic spot types in 『Muisanji(武夷山志)』, there are 38 types of scenery description in the painting, of which, the three scenery of big rock, peak, small rock occupy the vast majority. This reflects the Danxia(丹霞) landform characteristics of Wuyi-Gugok. The cultural connotation of Wuyi Mountain expressed and contained in the painting is analyzed and interpreted, and it is found that the Jiuqu(九曲) River in the Wuyi Mountain has Neo-confucianism culture, Taoism culture, Buddhism culture, Tea culture and so on. In addition, among the 171 scenery names shown in the painting, there are altogether 7 stone inscriptions that are consistent with or have the same meaning as the rock inscriptions site, including 3 for inscriptions praising the landscape, 3 for philosophical inscription and 1 for auspicious language inscription, which is considered as the important basis for the mutual textuality between the pictures and the stone inscriptions.